What is the estuary on southeast coast of South American formed by meeting Parana Uruguay rivers?

The estuary on the southeast coast of South America formed by the meeting of the Paraná and Uruguay rivers is called the Río de la Plata. It is a large estuary that stretches for about 290 km (180 mi) from the city of Buenos Aires, Argentina, to the Atlantic Ocean. The Río de la Plata is one of the widest estuaries in the world, with a maximum width of about 220 km (137 mi).